about_Scripting_ValidateCount.help.txt

TOPIC
    about_Scripting_ValidateCount
 
SHORT DESCRIPTION
    A brief tutorial on validating parameters by count
     
LONG DESCRIPTION
    Here’s another parameter validation attribute you might want to use in
    your PowerShell scripting and functions. If your parameter can take an
    array of values, you might want to limit that array to a certain size.
    For example, your parameter can take an array of computer names but you
    don’t want to process more than 5 for some reason. This is where
    [ValidateCount()] comes in to play.
 
    This attribute takes two values, the minimum number of accepted parameter
    values and the maximum.
 
    [ValidateCount(1,10)]
    [string[]]$Computername
     
    If used, this would mean I would need at least one computername but no
    more than 10. You could also set both values the same if you wanted an
    exact number:
 
    [ValidateCount(2,2)]
    [int[]]$Numbers
     
    Now, I’d have to pass exactly 2 numbers as parameter values. Let’s look
    at a more complete example.
 
    #requires -version 2.0
 
    Param (
    [Parameter(Position=0,Mandatory=$True)]
    [ValidateCount(1,5)]
    [string[]]$Name
    )
 
    Foreach ($item in $name) {
        #display the name in a random color
        Write-Host $item -ForegroundColor ([system.consoleColor]::GetValues(
        "system.consolecolor") | get-random)
    }
     
    This simple script writes each name in a random color, assuming I pass
    no more than 5 names.
 
    If I exceed that count, PowerShell will throw a tantrum (I mean exception).
 
    When you use this validation test, be sure your parameter is set to
    accept an array of values, e.g. [string[]].
 
SEE ALSO
    about_Functions_Advanced_Parameters
    http://jdhitsolutions.com/blog